Titration of citric acid in juice: Technical Notes · MSDS Sodium hydroxide solution would normally be made up by dissolving solid sodium hydroxide in deionised water to give a very

Page|25 TechnicalNotes-Titrationofcitricacidinjuice–StIgnatiusCollegeGeelong

T E C H N I C A L N O T E S

Titrationofcitricacidinjuice:TechnicalNotes

IntroductionThisisafairlystandardtitrationexceptforthefollowing:

• commerciallemonjuiceisused.Thisjuiceisslightlycoloured;and

• commerciallemonjuicehasatotalacidconcentrationthatisaround1M.Thisneedsdilutionbeforeuse.


Equipmentandmaterials• Safetyglassesandglovesfor

eachstudent

• Citricjuicesamples

• NaOHsolution(approx.0.1molL-1).

• Phenolphthaleinindicator

• Burette

• Retortstand

• Buretteclamp

• Pipette

• Pipettefiller(bulb)

• Titrationvessel(conicalflask)

• Beakers

• Funnel

• Whitetile

Riskmanagement• Thereisapossibilitythatincorrectlyusedglasswaremight

break,causingcutsorotherinjury.Withappropriateinstructionontheuseofburettes,pipettesandotherglassware,thereislowrisk.

• Fillingtheburettewhiletheburetteisplacedonabenchtopposestheriskofeyeinjurysincethesolutionsarebeingtransferredaboveeyelevel.Theburettestand(andtheburette)shouldbeplacedonthefloorwhilefilling,sothatthetopoftheburetteisbeloweye-level.

• Phenolphthaleinindicatorisflammable:keepawayfromignitionsources.Theamountsandconcentrationsofphenolphthaleinindicatorusedinthisexerciseposelowrisk.


• Sodiumhydroxideiscorrosive.Theconcentrations(0.1M)ofsodiumhydroxideusedinthisexerciseposelowrisk.Studentsshouldweargloves,andimmediatelycleanupanyspills.

Studentsmustneverpipettebymouth:theymustalwaysusepipettefillers.

Studentsmustwearsafetyglasses/goggles.

MSDSSodiumhydroxidesolutionwouldnormallybemadeupbydissolvingsolidsodiumhydroxideindeionisedwatertogiveaverydilutesolution.ThisisatypicalMSDSforaconcentratedsodiumhydroxidesolution.<http://msds.orica.com/pdf/shess-en-cds-010-000031006701.pdf>.









PhenolphthaleinIndicatorsolutionisavailableindifferentconcentrationsandindifferentsolvents.ThisisatypicalMSDS.<http://file.southernbiological.com/Assets/Products/Chemicals/Stains_and_Indicators-Powders/SIP13_5-Phenolphthalein/SIP13_5_MSDS_2011_Phenolphthalein.pdf>.






SuppliersLemonjuicecanbesourcesfromanysupermarket.Forexample,thefollowingisavailablefromWoolworths:

• WoolworthsSelectLemonJuice500mL


Sodiumhydroxide(draincleaner)canalsobesourcedfromasupermarket.Itwillbeoflowerpuritythansodiumhydroxidefromaspecialistchemicalsupplier.Sincesodiumhydroxideishydroscopic,anysodiumhydroxideshouldbestandardisedbeforeuse.

PreparationsuggestionsTheamountoftotalacidinlemonjuiceisapproximately1molL-1.Thelemonjuiceshouldbedilutedbymixing1volumeoflemonjuicewith9volumesofdeionisedwater.500mLlemonjuicewillmakeup5Lofdilutedlemonjuice.

StoragesuggestionsSodiumhydroxidesolutionshouldbefreshlymadewithinafewdaysasthesolutionwillreactwithcarbondioxideintheatmosphere.Anysodiumhydroxidesolutionthathasbeenstoredformoreafewdaysshouldbere-standardisedbeforeuse.

CopyrightandCreativeCommonsThemoralrightsoftheauthors,KieranLim,EliseMeehan,JessicaSaw,PetaWhite,JohnLong,andIanBentley,havebeenassertedundertheAustralianCopyrightAct1968(Cth).Exceptinglogos,trademarksorotherthird-partycontentasindicated,thisresourceisdistributedunderaCreativeCommons‘Attribution-NonCommercial-ShareAlike’4.0InternationalLicense.

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Titration of citric acid in juice: Technical Notes · MSDS Sodium hydroxide solution would normally be made up by dissolving solid sodium hydroxide in deionised water to give a very